Ground Water[JOURNAL]
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200 papers
Mapping the Spatial Sensitivity of Aquitard Hydraulic Parameters on Pumping Test Drawdowns.
van Leer MD, Zaadnoordijk WJ, Zech A … +2 more , Griffioen J, Bierkens MFP
Ground Water · 2026 · PMID 40855764 · Full text
This study investigates the spatial and temporal sensitivity of aquitard hydraulic conductivity and specific storage on drawdowns in pumping tests. The objective is to understand which area of the aquitard is represented...
This study investigates the spatial and temporal sensitivity of aquitard hydraulic conductivity and specific storage on drawdowns in pumping tests. The objective is to understand which area of the aquitard is represented by drawdowns in different observation wells. A three-layered MODFLOW 6 model was used to simulate pumping tests on a circular Voronoi grid for three transmissivity scenarios and both confined and semiconfined top boundary conditions. A local sensitivity analysis was performed using PEST++ to determine how perturbations in hydraulic conductivity and specific storage of the aquitard affect head changes at observation wells in the pumped and overlying aquifer. Results indicate that for observation wells in the pumped aquifer, sensitivity forms an elliptical shape that is symmetrical around the observation well and the pumping well for all scenarios. The sensitivity map for the observation well in the overlying aquifer depends on the transmissivity ratio between both aquifers. It favors the area surrounding the pumping well if the transmissivity of the pumped aquifer is lower than that of the overlying aquifer. Conversely, with higher transmissivity in the pumped aquifer, sensitivity primarily lies around the observation well. Sensitivity patterns evolve over time, expanding the area of influence and shifting the sensitivity toward the observation well for a semiconfined top boundary. These findings are relevant for understanding the information regarding aquitard heterogeneity that is present in pumping test drawdowns and optimizing pumping test design.
Groundwater Potential Mapping: A Misused and Dubious Concept.
Bradbury KR
Ground Water · 2025 · PMID 40833254 · Publisher ↗
Abstract loading — click title to view on PubMed.
Groundwater Recharge in a Fire-Adapted, Semi-Arid Forest: A Watershed Water Balance Approach.
Denver C, Springer AE, Dymond SF … +1 more , O'Donnell FC
Ground Water · 2025 · PMID 40808400 · Full text
Climate change induced aridity and Euro-American settlement have altered the historical disturbance and flow regimes of large portions of the ponderosa pine forests of northern Arizona. The increased occurrence of high-s...
Climate change induced aridity and Euro-American settlement have altered the historical disturbance and flow regimes of large portions of the ponderosa pine forests of northern Arizona. The increased occurrence of high-severity wildfires due to these changes has led to the establishment of various forest restoration programs to protect the region's forests and their watersheds. In 2014, a paired-watershed monitoring project was implemented to compare the impacts of differing levels of forest thinning to watershed hydrology in seven experimental watersheds nested within the Upper Lake Mary (ULM) watershed in Arizona. This study expands the calibration phase of the ULM paired-watershed by synthesizing historic precipitation, surface runoff, groundwater recharge, soil moisture data, and evapotranspiration (ET) data to perform regression analyses and create a holistic water balance for each watershed. The magnitude and timing of seasonal groundwater recharge events were quantified for the first time in this region using a water table fluctuation method. The results showed that recharge did not occur every year and was heavily dependent (P < 0.05) on total winter season precipitation and snowpack duration. On average, recharge composed 9% of the total water budget when present. The results of this study lay the foundation for a greater understanding of how forest restoration alters northern Arizona's forest hydrology and will provide crucial information that should be used in water policy and water resource decision-making as the region plans for future water availability.
A Data-Driven Simplified Nernst Equation for Estimating Reduction Potentials in Groundwater from pH and Temperature.
Bowman G, Harris G, Kirk M … +1 more , Jin Q
Ground Water · 2025 · PMID 40772816 · Full text
Reduction potentials of redox couples are fundamental for understanding subsurface geochemistry and guiding water resource exploration and management. Reduction potentials are routinely calculated with the Nernst equatio...
Reduction potentials of redox couples are fundamental for understanding subsurface geochemistry and guiding water resource exploration and management. Reduction potentials are routinely calculated with the Nernst equation, which requires detailed chemical composition data and complex speciation modeling-factors that limit its application in large-scale or data-limited field settings. To address these limitations, we developed a data-driven simplified Nernst equation that estimates the reduction potentials of individual redox couples using only pH and temperature. By integrating geochemical modeling with a global groundwater chemistry dataset, we demonstrate that pH is the dominant control on redox potential, while temperature and redox species activity play secondary roles. The resulting formulation reduces computational demands while maintaining high-predictive accuracy across diverse groundwater environments. This approach enables rapid and scalable estimation of reduction potentials, supporting applications in geochemical modeling, contaminant transport prediction, and groundwater quality assessments. Furthermore, it offers a thermodynamically grounded yet practical framework for interpreting electron transfer dynamics in natural groundwater systems.
Cave Diving Documents Spatial and Temporal Water Quality Variability in a Phreatic, Karst Cave System.
Kamal M, Spellman P, Kim S
Ground Water · 2025 · PMID 40741888 · Publisher ↗
Karst aquifers have evolved secondary porosity features that facilitate heterogeneous recharge and groundwater flow dynamics. These dynamics affect the natural spatial and temporal variability of water quality in the aqu...
Karst aquifers have evolved secondary porosity features that facilitate heterogeneous recharge and groundwater flow dynamics. These dynamics affect the natural spatial and temporal variability of water quality in the aquifer. However, when recharge occurs near urban and agricultural land use that can introduce contamination, the contamination can conflate natural water quality variability, generating convoluted signals in time and space. Most water quality investigations in karst aquifers rely on groundwater sampling at discrete locations such as wells or springs, which do not always capture the magnitude of water quality heterogeneity. Cave diving in phreatic caves can be used to explore this variability by using water quality sensors and discrete water chemistry samples to explore spatial and temporal water quality changes for improved and targeted water resource management. Our study uses cave diving to document the spatial and temporal variation in water quality within a phreatic cave system in the Floridan Aquifer System (FAS), a karst aquifer in northern Florida. We collect continuous 15-s measurements of dissolved oxygen (DO), temperature, pH, and specific conductance along a 1.1 km transect, which intersects multiple cave passages that drain into the primary cave passage. We also collect discrete water chemistry samples in three separate cave passages within the phreatic cave, as well as at the spring vent, to document spatial and seasonal variability in nutrients, organic matter, and major groundwater ions. Our results show that specific conductance, DO, temperature, and pH vary together spatially in consistent ways, which we use to identify cave passages that receive more direct recharge. Spatial and temporal variability across the cave system was most pronounced for NO-N (nitrate + nitrite), DO, and dissolved organic carbon, while major ions showed minimal spatial variability but greater temporal variability. Relationships derived between specific conductance and NO-N show a positive correlation, while relationships between ions associated with carbonate mineralogy and specific conductance are negatively correlated, which likely reflects the impact of recharge from agricultural land use surrounding the cave system. Our results highlight water quality complexity in phreatic caves and have implications for local water quality restoration efforts, interpreting water quality data collected at a discrete location, and provide guidance for future water quality studies in phreatic cave systems.
An Alternative Approach to Acquiring Permeability from Ultrasonic S-Wave.
Li G, Wang L, Liu Z
Ground Water · 2025 · PMID 40708555 · Publisher ↗
Water interaction between fractures and rock matrix is one of the themes in hydrogeology. Accurate values of Darcy permeability (k) of the matrix are desired for better quantification of the water interaction. In contras...
Water interaction between fractures and rock matrix is one of the themes in hydrogeology. Accurate values of Darcy permeability (k) of the matrix are desired for better quantification of the water interaction. In contrast to the traditional method using seepage experiments to measure k of a rock, this study uses the technique of ultrasonic shear (S-) wave for determining k of the rock matrix. From the perspective of waves, Darcy seepage is driven by slow compressional (P-) wave at very low frequencies, and k is associated with slow P-wave in the regime of low frequency. Similarly, there is another permeability associated with S-wave, namely, S-wave permeability (k). The rock samples are Navajo sandstone and Berea sandstone. Data of the dry sandstones with water are entered into Biot theory for yielding saturated phase velocity (V) and the quality factor due to viscous fluid (Q). Then, ultrasonically measured V and Q are fitted with the use of the model output. For Navajo sandstone, low-frequency k appears to be 0.107-0.115 darcy, surprisingly close to k of 0.1 darcy. For Berea sandstone, low-frequency k turns out to be 0.081 darcy, also consistent with k of 0.075 darcy. The success robustly shows that Biot theory is applicable to S-wave in isotropic rock free of fractures. More importantly, the comparability between low-frequency k and k demonstrates that ultrasonic S-wave is an alternative approach to acquiring k of the matrix.
Addressing the Problem of Hard-to-Reach Unpublished Data from Theses in University Repositories.
Venegas-Quiñones HL, Garcia-Chevesich PA, Guillen M … +2 more , Alejo F, McCray JE
Ground Water · 2025 · PMID 40671367 · Publisher ↗
Researchers frequently encounter challenges in accessing valuable data encapsulated within university theses, which are predominantly archived in PDF format and remain unpublished in repositories. These documents often e...
Researchers frequently encounter challenges in accessing valuable data encapsulated within university theses, which are predominantly archived in PDF format and remain unpublished in repositories. These documents often encompass original research, including vital environmental and hydrological data, yet they pose difficulties for searching or analysis due to inconsistent formatting and inefficient repository search tools such as keyword searches, which lead to an overwhelming list of documents. Our research team, engaged in developing a groundwater database for the Arequipa region of Peru, encountered this issue directly, with numerous relevant theses dispersed across local university repositories. The manual review process proved excessively time-consuming, necessitating the development of an innovative, automated solution. Our multi-step methodology commenced with optical character recognition (OCR) and Python scripts for keyword scoring, followed by the employment of Large Language Models (LLMs), notably Google's Gemini and the locally hosted Ollama, to semantically analyze content. This facilitated the identification and extraction of pertinent data (e.g., water quality parameters, well locations) and its organization into usable formats such as Excel spreadsheets; subsequent manual checks confirmed a high level of accuracy. The final system enables users to query an extensive number of documents swiftly and contextually, effectively overcoming traditional keyword search limitations. The tool is presently being disseminated among local researchers and institutions, offering a robust solution for accessing and managing regional groundwater data. This methodology possesses the potential for global scaling and adaptation, thereby enhancing access to gray literature and expediting scientific discovery across various disciplines.
Wellbore Skin: Why Its Presence and Properties Are So Difficult to Predict.
Houben GJ, Halisch M, Dohrmann R … +4 more , Lamparter A, Ufer K, Damian C, Boz D
Ground Water · 2025 · PMID 40641070 · Full text
The presence of positive wellbore skin, that is, deposits of fine-grained particles from the drilling fluid on the borehole wall, significantly affects the efficiency of water wells. Previous studies of skin samples have...
The presence of positive wellbore skin, that is, deposits of fine-grained particles from the drilling fluid on the borehole wall, significantly affects the efficiency of water wells. Previous studies of skin samples have shown a significant variability in typology, thickness, and composition but were largely unable to explain the differences. In order to overcome this problem, we therefore (1) significantly expanded the sample data base by investigating skin samples from nine wells with very similar geological and technical conditions and (2) investigated the evolution of the density of drilling fluids during the drilling. The former is done in order to evaluate differences in skin thickness and composition, and the latter to study the differential mobilization of particles. Incohesive and poorly sorted layers form the source of the particles, while the thickest accumulation of particles occurs in highly permeable layers, where the highest exfiltration rates initially occur. For well drillers, we recommend continuous monitoring of drilling fluid density to obtain a measure of the presence of particle-providing layers and the probability of wellbore skin formation.
A Century (1906-2024) of Groundwater and Land Subsidence Studies in Greater Houston Region: A Review.
Turco MJ, Greuter A, Wang G
Ground Water · 2025 · PMID 40635381 · Full text
The Greater Houston region has undergone substantial land subsidence over the past century, with rapid subsidence occurring from the late 1940s to the 1970s and more controlled rates thereafter. The establishment of the...
The Greater Houston region has undergone substantial land subsidence over the past century, with rapid subsidence occurring from the late 1940s to the 1970s and more controlled rates thereafter. The establishment of the Harris-Galveston Subsidence District (HGSD) in 1975 marked a pivotal milestone in subsidence management, primarily by regulating previously uncontrolled groundwater extraction. HGSD's success in reducing subsidence while simultaneously fostering robust economic growth in the Houston area inspired the creation of the Fort Bend Subsidence District (FBSD) in 1989. By 2024, significant subsidence (>0.3 m from 1906 to 2024) had impacted an area of approximately 12,000 km, encompassing nearly all of Harris and Galveston Counties, as well as parts of the surrounding counties. This subsidence led to an irreversible loss of around 12 km of groundwater storage capacity-equivalent to 60 times the volume of Lake Houston, or roughly 8 years' worth of water usage for Harris and Galveston Counties as of 2023. About 65% of this loss occurred before HGSD regulations (1906-1978), 20% between 1979 and 2000, and 15% since 2001. Due to groundwater regulations, the extent of subsidence has decreased significantly since the 1990s. By the early 2020s, the areas experiencing subsidence rates exceeding 1 cm/year had decreased to 1500 km, roughly one-twentieth of the greater Houston region, with only 50 km seeing rates above 2 cm/year. The highest current subsidence rate, approximately 3 cm/year since 2020, occurs in the Katy area, Fort Bend County. This review provides a comprehensive overview of land subsidence and groundwater level monitoring in the greater Houston region, highlighting regulatory developments, technological advancements, key research findings, and the continuing challenges of achieving sustainable groundwater management.
Estimation of Hydrogeologic Parameters at the Cape Cod Hydrology Research Site.
Székely F
Ground Water · 2025 · PMID 40624886 · Publisher ↗
The article deals with computer analysis of flow to pumping well partially penetrating the high conductivity porous water table aquifer. Water level depletion in the pumping well, 3 partially penetrating observation well...
The article deals with computer analysis of flow to pumping well partially penetrating the high conductivity porous water table aquifer. Water level depletion in the pumping well, 3 partially penetrating observation wells, and 6 piezometers of short screen are evaluated in the analysis. The WT software considers the delayed gravity drainage caused by dewatering of the overlying unsaturated zone. This flow is emulated as diffusive crossflow or leakage from an aquitard with an impervious top. The analytical method by Hantush (1962) is applied to confirm the aquifer parameters using the late time drawdown data in all observation wells and piezometers. The software PEST is employed to optimize the aquifer properties and the presumably laminar specific radial loss parameter of the pumping well. The results are compared with two earlier analyses. The k and k parameters fit the relevant data by Moench et al. (2001), whereas the S parameter is close to the value by Tartakovsky and Neuman (2007). An intermediate value is found for the S parameter.
Variability and Scale Dependence of Hydraulic Conductivity for Hanford Site Sand and Gravel Aquifers.
Khaleel R
Ground Water · 2025 · PMID 40579905 · Publisher ↗
This study presents a comprehensive compilation of a hydraulic conductivity (K) database (over 800 measurements) collected over the past seven decades, encompassing test volumes ranging from laboratory to field scales fo...
This study presents a comprehensive compilation of a hydraulic conductivity (K) database (over 800 measurements) collected over the past seven decades, encompassing test volumes ranging from laboratory to field scales for two principal sedimentary units at the Hanford site in south-central Washington State. Despite both units being gravel-dominated, the geometric mean K of the Hanford formation is orders of magnitude higher than that of the Ringold Formation for the permeameter and pumping test data. In contrast, the lnK variance across test volumes shows only moderate variation between the two units. Analysis of K values across different support scales reveals a clear scale dependence for the Hanford formation, contrasting with Ringold, which exhibits scale-invariant behavior at the field scale. These differences arise from their distinct depositional processes; while the Ringold Formation was deposited gradually over geologic time by fluvial systems, producing consistent K, the Hanford formation was deposited abruptly by catastrophic glacial floods, leading to scale-dependent K variability. The study underscores that scale dependence in unconsolidated sand and gravel aquifers is common but not universal. Calibrated inverse modeling of regional groundwater flow yields high K estimates, with the average for the Hanford formation paleochannel being ~15,000 m/d, ranging from 1002 to 21,514 m/d. Multiple lines of evidence, including pumping tests, support these model-calibrated high K estimates for the Hanford formation paleochannel comprised of open framework gravels. For both sedimentary units, the upscaled K estimates align with the inverse model-calibrated estimates for non-channel portions of the Hanford and Ringold formations. While previous studies examined scale dependence using data from multiple sites, this study focuses on a single site with two sedimentary units analyzed across multiple support scales. To the best of our knowledge, this represents the most extensive compilation of K data for two gravel-dominated formations at the same site, incorporating both laboratory and field test results across varied scales.
The Aqueducts and Water Supply of Ancient Jerusalem.
Deming D
Ground Water · 2025 · PMID 40548822 · Full text
Jerusalem, a city held sacred by three of the world's great religions, is located in a semi-arid climate, and its occupation through the millennia has only been made possible by the construction of an extensive and ingen...
Jerusalem, a city held sacred by three of the world's great religions, is located in a semi-arid climate, and its occupation through the millennia has only been made possible by the construction of an extensive and ingenious water supply infrastructure. The settlement of Jerusalem was first made possible by water from the Gihon Spring. Over the centuries, the inhabitants of Jerusalem added several pools and reservoirs to collect and store water. Nearly all buildings, both private and public, also had extensive storage capacity in the form of cisterns. To support a burgeoning population and pilgrim growth during the late Second Temple Period, four aqueducts were constructed to bring additional water into Jerusalem. Much work remains to identify, date, classify, and restore the ancient water works of this great city.
Spatiotemporal Differences of Groundwater Recovery in North China Plain Using GRACE and Well Data.
Zhang H, Wang L, Peng Z … +1 more , Hu L
Ground Water · 2025 · PMID 40498054 · Publisher ↗
The long-term depletion of groundwater storage (GWS) in the North China Plain (NCP) has recovered recently, but the spatiotemporal characteristics of this recovery and its driving factors are still unclear. For this stud...
The long-term depletion of groundwater storage (GWS) in the North China Plain (NCP) has recovered recently, but the spatiotemporal characteristics of this recovery and its driving factors are still unclear. For this study, we estimated the GWS in the NCP using data from the Gravity Recovery and Climate Experiment (GRACE) and its Follow-On mission (GRACE-FO) and in situ well measurements. We quantified the spatiotemporal characteristics and the drivers for the transition from long-term GWS depletion to its rapid recovery in the NCP. To identify the turning point of the GWS recovery time, we used the Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (ICEEMDAN) method combined with the Bayesian Estimator of Abrupt Change, Seasonality, and Trend (BEAST) algorithm. The result shows that the GWS recovery in the southern NCP (February 2020 to October 2020) occurred earlier than in the northern NCP (November 2020 to August 2021). The GWS recovery was detected 7 months earlier in in situ wells compared with satellite data. This discrepancy is attributable to the differences in the data resolution between the spatial and in situ well measurements, as well as the more drastic response of in situ wells to groundwater changes. Both precipitation and the South-to-North Water Diversion (SNWD) project affected GWS recovery, leading to the observed spatiotemporal differences. The contributions to annual GWS changes (i.e., annual ΔGWS) from climatic and human factors were further quantified. Our results indicate that climate was the dominant driver, accounting for 87.63% of the annual ΔGWS in the NCP, while human activities contributed 12.37%.
Saline Groundwater for Aquaculture: An Expanding Hydrogeological and Hydrogeophysical Frontier.
Kurylyk BL
Ground Water · 2025 · PMID 40485588 · Full text
Given the chronic and multi-faceted challenges of marine aquaculture, there is growing interest in land-based aquaculture supported by high-capacity saltwater wells. These wells can theoretically provide a stable, high-q...
Given the chronic and multi-faceted challenges of marine aquaculture, there is growing interest in land-based aquaculture supported by high-capacity saltwater wells. These wells can theoretically provide a stable, high-quality source of saline groundwater for aquaculture tanks. In this Issue Article, I focus on saltwater wells installed in the salt wedges of coastal aquifers and argue that these wells could benefit or harm local homeowners or municipalities relying on nearby freshwater wells. More research in the fields of hydrogeophysics and physical and contaminant hydrogeology is critically needed to better understand how high-capacity saltwater wells may impact coastal aquifers and groundwater-dependent communities. Such work is crucial for informing the development of scientifically based regulations for the management of these wells and related aquaculture operations. Appropriate regulations would protect coastal communities, ecosystems, and industrial operators from potentially negative impacts of saltwater wells and would help to maximize their potential benefits.
Collaborative Science for Groundwater Biodiversity Conservation.
Saccò M, Huggins X, Martínez A … +1 more , Reinecke R
Ground Water · 2025 · PMID 40476347 · Full text
Abstract loading — click title to view on PubMed.
Microplastic Pollution Characteristics and Risk Assessment in Groundwater of Chengdu, China.
Chen J, Wang P, Li P … +5 more , Peng X, Chen Y, Yong X, Huang J, Deng Y
Ground Water · 2025 · PMID 40418205 · Publisher ↗
Microplastic pollution has emerged as a critical issue within the global environmental landscape. Nevertheless, our understanding of the occurrence and distribution of microplastics in groundwater systems remains limited...
Microplastic pollution has emerged as a critical issue within the global environmental landscape. Nevertheless, our understanding of the occurrence and distribution of microplastics in groundwater systems remains limited. In this study, we examined the contamination of microplastics in groundwater across Chengdu, located in western China. The findings revealed that the concentration of microplastics varied between 7.0 and 24.0 particles/L. Microplastics measuring less than 1000 μm in size constituted the majority, with granules and fragments being the main shapes. Furthermore, the predominant polymer types included polyphenylene sulfide (PPS), polyethylene terephthalate (PET), polyethylene (PE), and polyamide (PA). The pollution load index showed that all groundwater monitoring stations were contaminated with microplastics. An assessment of the polymeric and pollution risks demonstrated a spectrum of variability, ranging from low- to high-risk levels. An increase in the abundance of microplastics and toxic polymers correlates with elevated potential ecological risk levels associated with these contaminants. This study provides novel insights into the contamination of microplastics in groundwater. The risk assessments establish a foundational baseline for future comprehensive evaluations and the formulation of effective strategies aimed at establishing groundwater quality criteria, as well as pollution control and management.
Geochemistry at a Karst Spring Reveals Complex Stormflow Dynamics in an Eogenetic Karst Aquifer.
Spellman P, Pain A, Kim S … +1 more , Kamal M
Ground Water · 2025 · PMID 40370010 · Publisher ↗
The Floridan Aquifer System (FAS) is a triple porosity, eogenetic karst aquifer that contains extensive phreatic cave networks embedded in a high permeability carbonate matrix. These unique characteristics create complex...
The Floridan Aquifer System (FAS) is a triple porosity, eogenetic karst aquifer that contains extensive phreatic cave networks embedded in a high permeability carbonate matrix. These unique characteristics create complex flow dynamics that impact residence time distributions within the FAS, which are important to constrain for implementing effective water resource strategies. The impacts of eogenetic karst characteristics on seasonal and longer term hydrological dynamics have been previously evaluated; however, stormflow remains understudied. Our study explores stormflow dynamics at a karst spring in the eogenetic FAS after major Hurricane Idalia made landfall in August 2023. We analyze data from in-situ sensors that collect NO-N, specific conductance, and discharge at 15-min intervals to capture potentially small changes in chemistry that could be significant. We coupled the sensor data with grab sample collection of water isotopes and major element chemistry to provide additional details on the stormflow dynamics. Our results show at least two stormflow pulses as evidenced by changes in NO-N and confirmed geochemically; albeit the absolute changes in NO-N for both stormflow pulses were small (<0.005 mmol). One stormflow pulse was diluted with respect to NO-N while the other mobilized NO-N. The stormflow pulse that is associated with mobilized NO-N was detected for at least 19 days after the rain began from Idalia, indicating long residence times before evacuation from the cave system. Both of the detected stormflow pulses were superimposed on seasonal trends in NO-N that are known to occur, whereby it appears storms could amplify NO-N seasonal effects. Our results have implications for understanding complex residence times in eogenetic karst aquifers and highlight the influence of the carbonate bedrock matrix on stormflow through the FAS.
Hydraulic Response to Sea Level Rise in a Coastal Aquifer Extending under the Sea with a Cut-off Wall.
Wang S, Xu J, Zhang W … +2 more , Yi Z, Chen H
Ground Water · 2025 · PMID 40357881 · Publisher ↗
Seawater intrusion can cause the freshwater-saltwater interface to move inland toward coastal freshwater aquifers. Sea level rise has become a significant driver of this phenomenon. Installing cut-off walls along coastal...
Seawater intrusion can cause the freshwater-saltwater interface to move inland toward coastal freshwater aquifers. Sea level rise has become a significant driver of this phenomenon. Installing cut-off walls along coastal aquifers is an effective engineering measure to mitigate seawater intrusion. However, most analyses of groundwater flow under sea level rise, particularly with cut-off walls, primarily rely on numerical methods, with limited analytical approaches available. In this study, we developed mathematical models for groundwater flow induced by sea level rise, dividing the coastal aquifer into offshore and inland regions along the cut-off wall. An unknown flow function was introduced as a boundary condition at the shared boundary. Using homogenization and the finite Fourier transform method, we derived analytical solutions for the two regions separately. A global coupling solution, achieving hydraulic continuity between the two regions, was obtained by applying the collocation method at the shared boundary. The validity of the solution was confirmed through comparisons with finite difference numerical simulations. Furthermore, we analyzed the impacts of factors such as sea level rise amplitude and cut-off wall embedment depth on hydraulic changes. The results indicate that increases in the amplitude of sea level rise significantly amplify hydraulic head changes in the inland aquifers, while deeper embedment of the cut-off wall enhances its effectiveness in preventing seawater intrusion. However, the model does not consider density differences between freshwater and saltwater or the dynamics of the saltwater-freshwater interface.
Spatial Prediction Modeling of Geogenic Chromium in Groundwater Using Soft Computing Techniques.
Joodavi A, Sanikhani H, Majidi M … +1 more , Baghbanan P
Ground Water · 2025 · PMID 40353617 · Publisher ↗
The presence of chromium (Cr) in groundwater poses a significant threat to human health. However, the lack of testing in many wells suggests that the severity of this issue may be underestimated. In this study, various p...
The presence of chromium (Cr) in groundwater poses a significant threat to human health. However, the lack of testing in many wells suggests that the severity of this issue may be underestimated. In this study, various predictive models, including soft computing techniques such as gene expression programming (GEP), artificial neural networks (ANN), multivariate adaptive regression splines (MARS), and the M5 Tree model, along with random forest (RF) and multiple linear regression (MLR), were employed to estimate geogenic Cr concentrations in groundwater based on geological and geochemical parameters in northeastern Iran. A dataset of 676 Cr concentration measurements was used to train and evaluate the models. Among the methods tested, ANN demonstrated the highest predictive accuracy, followed closely by RF, which provided competitive results. GEP and MARS also showed reasonable performance, while MLR exhibited the weakest accuracy, highlighting the limitations of linear models in addressing complex geochemical processes. The ANN model identified over 600,000 individuals in the central and western regions of the study area as being at significant risk of geogenic Cr contamination in groundwater. The findings underscore the potential of advanced predictive models in groundwater quality management and their applicability in other regions with similar challenges.
Multi-Purpose Data Worth Assessment of a Surface Water-Groundwater and Nitrogen Transport Model.
Durney P, Di Ciacca A, Wilson S … +1 more , Wöhling T
Ground Water · 2025 · PMID 40326846 · Full text
Understanding which hydrological data types provide the most valuable information for models is crucial, given the limitations of data availability. This study applies data worth analysis to evaluate the impact of variou...
Understanding which hydrological data types provide the most valuable information for models is crucial, given the limitations of data availability. This study applies data worth analysis to evaluate the impact of various observation types on predictive uncertainty in a coupled SWAT-MODFLOW-RT3D model simulating water flows and nitrate transport in a small headwater catchment in New Zealand. We assessed the worth of continuous nitrate concentrations, in-catchment flow measurements, and SkyTEM-derived groundwater levels for predicting stream flow and in-stream nitrate concentrations. Using PEST software for model calibration and linear uncertainty analysis, we determined the relative worth of different observation types. Results indicate that SkyTEM estimates of groundwater levels and continuously measured nitrate concentrations were particularly effective in reducing predictive uncertainty. This study highlights the value of integrating high-resolution SkyTEM data into models to enhance prediction accuracy for groundwater levels, stream flow, and nitrate pollution. It also demonstrates nitrate's utility as an environmental tracer, refining our understanding of surface water-groundwater interactions and solute transport in the Piako Headwaters Catchment.
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